obs-studio/cmake/Modules/FindFFmpeg.cmake

#
# This module defines the following variables:
#
# FFMPEG_FOUND - All required components and the core library were found
# FFMPEG_INCLUDE_DIRS - Combined list of all components include dirs
# FFMPEG_LIBRARIES - Combined list of all components libraries
# FFMPEG_VERSION_STRING - Version of the first component requested
#
# For each requested component the following variables are defined:
#
# FFMPEG_<component>_FOUND - The component was found
# FFMPEG_<component>_INCLUDE_DIRS - The components include dirs
# FFMPEG_<component>_LIBRARIES - The components libraries
# FFMPEG_<component>_VERSION_STRING - The components version string
# FFMPEG_<component>_VERSION_MAJOR - The components major version
# FFMPEG_<component>_VERSION_MINOR - The components minor version
# FFMPEG_<component>_VERSION_MICRO - The components micro version
#
# <component> is the uppercase name of the component

find_package(PkgConfig QUIET)

if(CMAKE_SIZEOF_VOID_P EQUAL 8)
  set(_lib_suffix 64)
else()
  set(_lib_suffix 32)
endif()

function(find_ffmpeg_library component header)
  string(TOUPPER "${component}" component_u)
  set(FFMPEG_${component_u}_FOUND
      FALSE
      PARENT_SCOPE)
  set(FFmpeg_${component}_FOUND
      FALSE
      PARENT_SCOPE)

  if(PKG_CONFIG_FOUND)
    pkg_check_modules(PC_FFMPEG_${component} QUIET lib${component})
  endif()

  find_path(
    FFMPEG_${component}_INCLUDE_DIR
    NAMES "lib${component}/${header}" "lib${component}/version.h"
    HINTS ENV FFMPEG_PATH ${FFMPEG_PATH} ${CMAKE_SOURCE_DIR}/${FFMPEG_PATH}
          ${PC_FFMPEG_${component}_INCLUDE_DIRS}
    PATHS /usr/include /usr/local/include /opt/local/include /sw/include
    PATH_SUFFIXES ffmpeg libav include)

  find_library(
    FFMPEG_${component}_LIBRARY
    NAMES "${component}" "lib${component}"
    HINTS ENV FFMPEG_PATH ${FFMPEG_PATH} ${CMAKE_SOURCE_DIR}/${FFMPEG_PATH}
          ${PC_FFMPEG_${component}_LIBRARY_DIRS}
    PATHS /usr/lib /usr/local/lib /opt/local/lib /sw/lib
    PATH_SUFFIXES
      lib${_lib_suffix}
      lib
      libs${_lib_suffix}
      libs
      bin${_lib_suffix}
      bin
      ../lib${_lib_suffix}
      ../lib
      ../libs${_lib_suffix}
      ../libs
      ../bin${_lib_suffix}
      ../bin)

  set(FFMPEG_${component_u}_INCLUDE_DIRS
      ${FFMPEG_${component}_INCLUDE_DIR}
      PARENT_SCOPE)
  set(FFMPEG_${component_u}_LIBRARIES
      ${FFMPEG_${component}_LIBRARY}
      PARENT_SCOPE)

  mark_as_advanced(FFMPEG_${component}_INCLUDE_DIR FFMPEG_${component}_LIBRARY)

  if(FFMPEG_${component}_INCLUDE_DIR AND FFMPEG_${component}_LIBRARY)
    set(FFMPEG_${component_u}_FOUND
        TRUE
        PARENT_SCOPE)
    set(FFmpeg_${component}_FOUND
        TRUE
        PARENT_SCOPE)

    list(APPEND FFMPEG_INCLUDE_DIRS ${FFMPEG_${component}_INCLUDE_DIR})
    list(REMOVE_DUPLICATES FFMPEG_INCLUDE_DIRS)
    set(FFMPEG_INCLUDE_DIRS
        "${FFMPEG_INCLUDE_DIRS}"
        PARENT_SCOPE)

    list(APPEND FFMPEG_LIBRARIES ${FFMPEG_${component}_LIBRARY})
    list(REMOVE_DUPLICATES FFMPEG_LIBRARIES)
    set(FFMPEG_LIBRARIES
        "${FFMPEG_LIBRARIES}"
        PARENT_SCOPE)

    set(FFMPEG_${component_u}_VERSION_STRING
        "unknown"
        PARENT_SCOPE)
    set(_vfile "${FFMPEG_${component}_INCLUDE_DIR}/lib${component}/version.h")

    if(EXISTS "${_vfile}")
      file(STRINGS "${_vfile}" _version_parse
           REGEX "^.*VERSION_(MAJOR|MINOR|MICRO)[ \t]+[0-9]+[ \t]*$")
      string(REGEX REPLACE ".*VERSION_MAJOR[ \t]+([0-9]+).*" "\\1" _major
                           "${_version_parse}")
      string(REGEX REPLACE ".*VERSION_MINOR[ \t]+([0-9]+).*" "\\1" _minor
                           "${_version_parse}")
      string(REGEX REPLACE ".*VERSION_MICRO[ \t]+([0-9]+).*" "\\1" _micro
                           "${_version_parse}")

      set(FFMPEG_${component_u}_VERSION_MAJOR
          "${_major}"
          PARENT_SCOPE)
      set(FFMPEG_${component_u}_VERSION_MINOR
          "${_minor}"
          PARENT_SCOPE)
      set(FFMPEG_${component_u}_VERSION_MICRO
          "${_micro}"
          PARENT_SCOPE)

      set(FFMPEG_${component_u}_VERSION_STRING
          "${_major}.${_minor}.${_micro}"
          PARENT_SCOPE)
    else()
      message(STATUS "Failed parsing FFmpeg ${component} version")
    endif()
  endif()
endfunction()

set(FFMPEG_INCLUDE_DIRS)
set(FFMPEG_LIBRARIES)

if(NOT FFmpeg_FIND_COMPONENTS)
  message(FATAL_ERROR "No FFmpeg components requested")
endif()

list(GET FFmpeg_FIND_COMPONENTS 0 _first_comp)
string(TOUPPER "${_first_comp}" _first_comp)

foreach(component ${FFmpeg_FIND_COMPONENTS})
  if(component STREQUAL "avcodec")
    find_ffmpeg_library("${component}" "avcodec.h")
  elseif(component STREQUAL "avdevice")
    find_ffmpeg_library("${component}" "avdevice.h")
  elseif(component STREQUAL "avfilter")
    find_ffmpeg_library("${component}" "avfilter.h")
  elseif(component STREQUAL "avformat")
    find_ffmpeg_library("${component}" "avformat.h")
  elseif(component STREQUAL "avresample")
    find_ffmpeg_library("${component}" "avresample.h")
  elseif(component STREQUAL "avutil")
    find_ffmpeg_library("${component}" "avutil.h")
  elseif(component STREQUAL "postproc")
    find_ffmpeg_library("${component}" "postprocess.h")
  elseif(component STREQUAL "swresample")
    find_ffmpeg_library("${component}" "swresample.h")
  elseif(component STREQUAL "swscale")
    find_ffmpeg_library("${component}" "swscale.h")
  else()
    message(FATAL_ERROR "Unknown FFmpeg component requested: ${component}")
  endif()
endforeach()

include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(
  FFmpeg
  FOUND_VAR FFMPEG_FOUND
  REQUIRED_VARS FFMPEG_${_first_comp}_LIBRARIES
                FFMPEG_${_first_comp}_INCLUDE_DIRS
  VERSION_VAR FFMPEG_${_first_comp}_VERSION_STRING
  HANDLE_COMPONENTS)

if(FFMPEG_FOUND)
  foreach(component ${FFmpeg_FIND_COMPONENTS})
    if(NOT TARGET FFmpeg::${component})
      string(TOUPPER ${component} component_u)
      if(FFMPEG_${component_u}_FOUND)
        if(IS_ABSOLUTE "${FFMPEG_${component_u}_LIBRARIES}")
          add_library(FFmpeg::${component} UNKNOWN IMPORTED)
          set_target_properties(
            FFmpeg::${component}
            PROPERTIES IMPORTED_LOCATION "${FFMPEG_${component_u}_LIBRARIES}")
        else()
          add_library(FFmpeg::${component} INTERFACE IMPORTED)
          set_target_properties(
            FFmpeg::${component}
            PROPERTIES IMPORTED_LIBNAME "${FFMPEG_${component_u}_LIBRARIES}")
        endif()

        set_target_properties(
          FFmpeg::${component}
          PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
                     "${FFMPEG_${component_u}_INCLUDE_DIRS}")
      endif()
    endif()
  endforeach()
endif()